allthe, I don't understand how you can have 'specifically designated' groups without excluding someone?
I would a little take issue with this: 'I don't see the need to publically ban them from attending the conference if they wouldn't want to attend anyway.'
I used to think this too. But the whole situation has become very antagonistic and politicized. A good example, as I said above, is the use of the words 'cis' and 'trans': I get told I am being rude or transphobic if I do not use the word 'cis' to describe myself. You're describing a live-and-let-live approach, but I don't think that is how others approach it.
I wish it were. I wish it were ok to say, look, this conference is going to be about x, y and z. If you want to tak about a,b, and c, that is not what we're doing. But that isn't what happens.
I really noticed this at Reclaim the Night in London last year. You'd think that if someone wanted to be recognized as a woman, they would just turn up and march, and identify as a woman in solidarity with the other women. Instead, part way through a group of people pushed through the march, carrying some kind of red flags or something that made them very visible. They were MtoF transsexuals who felt that the best way to show they were women was to push through a march full of women announcing their solidarity and carrying placards making very personal statements about rape ... and to show they were visibly a different group.
Why on earth would anyone do that?!
I should say, I am sure this is only a small number of people, I'm sure lots of people would never have thought of doing this, but maybe it helps explain why this is not just a one-sided issue.